Historically, people first wore shoes to protect their feet. Over the centuries, footwear evolved into many different types that were specific to particular activities. Thus, the protection offered by a cold-weather work boot is highly different from that offered by a running shoe. In addition to protecting the feet, athletic footwear has further developed to offer specific functions dependent on the particular sport. Soccer shoes, for instance, have spikes for traction, whereas cycling shoes have very stiff soles with mounting plates for cleats to engage the pedal. In this manner, golf shoes have evolved to provide the wearer with good traction on grass, comfort while walking, and a stable platform for hitting the ball. Typical golf shoes have had a relatively stiff sole with metal spikes or plastic cleats.
A stiff sole, while providing a stable platform, can nonetheless cause discomfort because there is a balance between how the foot should be allowed to move versus how it should be supported. An example of this is the fact that during walking and at the start and finish of the golf swing, the foot bends at the metatarsal joints (the ball). Aside from the physical effort needed to flex a very stiff sole (which would tend to cause a ‘clunky’ gait as when wearing clogs), sole stiffness tends to cause the heel of the foot to slide up and down in the heel cup, potentially causing blisters. Thus, golf shoes have evolved to have soles that flex across the ball area to allow this movement without compromising the lateral stability of a good hitting platform.
However, relatively recent studies in biomechanics have sought to better quantify how the 26 bones of the foot move relative to each other during human movements. One particular motion that has been identified is a torsional movement about the long axis of the foot. In effect, the forefoot and rear foot twist relative to each other. It is thought that this movement smoothes the contact between foot and ground, decreasing impacts with the ground as well as providing better ground contact. This observation has led to the development of a golf shoe sole to allow this natural movement.
U.S. Pat. No. 3,550,597 discloses a device that facilitates the natural rolling action of the foot during movement by providing a flat construction with front and rear main lifting sections rigidly connected to a resilient intermediate section that is twisted into the form of a flat torsion spring. The device applies a yieldable torsion action during use that is applied to the foot by the lifting sections, whereby the heel of the foot is urged upwardly at the inner side and the forefoot is raised upwardly at the outer side, producing a torsion action similar to the natural torsion action of the foot.
Another construction intended to provide greater support to the wearer of the shoe is disclosed in U.S. Pat. No. 5,926,974 to Friton. The Friton shoe has a sole that is not designed for golf, but for hiking. It discloses the use of pods and lugs for traction elements that in combination provide greater traction or irregular ground conditions. However, the teachings of this patent are atypical of what is required for a golf shoe. Patent '974 discloses a plurality of pods that are relatively soft, such that they may fan out and serve as compression cushions therein increasing the area of ground contact to improve traction, much the way the hoofs of a mountain goat react. The present invention utilizes relatively hard pods for an entirely different type of terrain.
There remains a need for an improved outsole for a golf shoe that enables an individual movement of the foot, particularly, the rotation between the rear foot and the forefoot, flexing across the foot of the wearer, and also the ability of the shoe to provide flexibility not just across but longitudinally along the metatarsal area of the foot.